Hydraulic expansion bar



Dec. 18 1923. HAWJME D. v. SLCKMAN HYDRAULIC EXPANSION BAR Filed Sept. 19. 1921 2 Sheets-Sheet 1 l A, 33 Snowmoz I [9. W. da /imam.

" attozncqw L WZGM D. V. SECKMAN HYDRAULIC EXPANSION BAR Dec 18 Filed Sept. 19. 1921 2 Sheets-Sheet 3 L lla!! Q. WC flmwa Patented cc. 18, 1923.

DAVY VANCE SICKMAN, OF DENVER, COLORADO.

HYDRAULIC EXPANSION BAR.

Application filed. September 19, 1921. Serial No. 501,811.

To all whom it may concern Be it known that I, DAVY VANOE S101:- MAN, a citizen of the United States, residing at the city and county of Denver and State of Colorado, have invented certain new and useful Improvements in Hydraulic Expansion Bars; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the characters of reference marked thereon, which form a part of this specification.

This invention relates to hydraulic bars of the type used for shearing and breaking coal in'what is known as the powderless method of mining coal.-

In mining coal without the use of powder the coal is undercut in the usual way, and at a suitable height above the undercut holes, either round or rectangular, are bored. Into these holes hydraulic bars are inserted. The bars are usually provided with chambers spaced at suitable distances along the bar and provided with pistons. Liquid, under pressure, is forced into the chambers and causes the pistons to move outwardly'thus subjecting the coal to enormous stresses which shear the coal vein and break the coal. Some of the later and better types of bars have each chamber provided with a pair of opposed pistons in order to prevent the bar from being subjected to undue strains. As examples of thesebars', reference may be had to the following patents which have been granted to me: 1,225,062 dated May 8, 1917'; 1,14:1,077dated'May25, 1915; 1,191,138 dated July 11, 1916 1,278,393dated Sept. 10, 1918'." i

It has been found that considerable dlffi'. culty is experienced in the operation of these bars for the reason that the pistons do not always resume their initial or collapsed position when the pressure is removed from the liquid. Even wherethe pressure pumps are .reversed so as to act'as suction pumps, the pistons do not always return. This may be due to the fact that the packing is applied with a view of withstanding great pressures from. the inside but such packing will usuallyaclmit air into the chambers when suction is resorted to for collapsing the pistons.

The object of my invention is to overcome the objection noted above and provide means that will automatically return the pistons to their initial or collapsed position, when the pressure is removed from the liquid, without'depending on suction'and the collapsing effect due to the external atmospheric pressure.

The object of my invention is obtained by means which I will now describe and which 'is illustrated in the accompanying drawings to which reference will be'made and in which- Fig. 1 is a side elevation of my improved bar showing the pistons in collapsed position and with part of the outer cover removed to disclose the mechanism.

Fig. 2 is a view similar to that of Fig. 1 but with the pistons in their expanded position.

Fig. 3 is a plan view of the bar with part of the outer'cover and two of the pistons removed.

Fig. 4 is a side elevation of a portion of a bar and shows a section containing two pistons, parts of the bar being broken away to show the location of a portion of the mechanism employed.

Fig. 5 is a view similar to that of Fig. 4 but in which the pistons are shown expanded.

Fig. 6 shows a detail of the guide bar and sleeve.

Fig. 6 shows an end view of the guide bar and cooperating sleeve.

Fig. 7 is a detail showing the bolt which is connected to the piston flange and same parts throughout the several views.

The bar 5 is usually of rectangular cross section and is provided with a plurality of chambers 6 spaced at suitable distances along the length thereof. YVithin each chamber are two pistons 7 and 8' which are connected with the bar and with each other by means disclosed in my former Patent 1,278,393 referred to above, or in mycopending application Serial No. 481,810 filed July 1, 1921 or in any other manner. In this application I have shown iny improvement applied to a bar having opposed pistons but it will be evident as the description proceeds that my improvement is entirely independcut of whether one or two pistons are used in each chamber. 7

The flanges 9 of pistons 7 and 8 are each provided with diametrically opposed openings 10, the outer part 11 being rectangular and provided with a shoulder 12, a slot 13 extending from said opening the entire thickness of the flange.

Holes 14 are provided in bar 5 directly beneath openings 10, for the reception of bolts 15 which are each provided with a square head 16 for cooperating with the rectangular portion of opening 10. Each of bolts 15 has a hardened steel pin 17 secured thereto by welding or other suitable means. Holes .14 are each provided with a slot 18 v for the reception of pins 17.

The bar 5 is also provided with additional I holes 19, two for each piston. Within the endof each of holes 19 is secured, by welding, or otherwise, a plug 20 having a central hub-like portion 21 through which extends a screw threaded opening 22 for the reception of a guide pin or rod 23. Slidingly connected to rod 23 is a sleeve 24 having a head 25 and an outwardly projectingpin 26. A coil spring 27 of suitable strength surrounds pin 23 and sleeve 2a and abuts agaainst plug 20 andhead 25. Holes 19 are each provided with slots 28 for the recep tion of pins 26.

Pivotally connected to bar 5 by. means of suitable pivots 29 are levers 30 one end or which has a slot 31 for the reception of pin 17 of bolt 15. A link 32 has one end pivot ally connected to lever 30 between its pivot 29 and the slot 31,the other end being connected to pin 26 of sleeve 24.. In assembling, the pistons 7 and 8 are collapsed as shown in Fig. 1 and spring 27 is compressed so as to put it under considerable tension before link 32 is connected to pin 26. If water, or other liquid, is now forced into chambers 6 and the pistons moved outwardly until they occupy the expanded position shown in Fig. 2, then pin 17 will rotate the lever 30'on its pivot 29 and move link 32 and pin 26 against the tension of spring 27. When the pressure is removed from between the pistons the action of spring 27 on pistons 7 and 8 through rod 15, pin 17, lever 30 and link 32 will cause them to move inwardly until they reach the collapsed position shown in Figs. 1 and 1. Each of the pistons is acted upon by two separate springs 27 whose force is transmitted to diametrically opposed points 10 by means of bolts 15 and levers and links 30 and 32 referred to above. It is, of course, evident that springs 27 will have to be undersuch initial tension that they will exert sufficient force to return the pistons to their fully collapsed position. i

The sides of bars 5 are covered by a suitable Sheet metal covering 33 which, serves to protect the levers from injury and which insures a smooth exterior surface that will not catch in the broken coal. Having thus described my invention or discovery and the manner of constructing and using the same what I claim is:

ed to said spring and to a point intermediate the ends of said lever, a bolt connected to the head of said piston andhaving a pin and slot connection with said lever.

'2; A hydraulic expansion bar having a plurality of chambers therein, a piston in each of saidchambers,.means comprising a liquid under-pressure for moving said pis-;

tons outwardly in said chamber and means for automatically returning said pistons to their initial position when the pressure is removed from said liquid, saidmeans com prising a spring secured tosaid bar, alever having one end pivoted to said bar, a link pivotally connected to said'spring and said lever, a bolt connected to each of said pistons and having a pin and slot connection with the end of said-lever.

3. A hydraulic expansion bar having a chamber therein, a pair of opposed pistons in each of said chambers, means comprising a liquid under pressure for moving said pistons outwardly in said chambers and spring means for automatically returning said pistons to their original position when the pressure is removed from the liquid, said means comprising a spring secured to said bar, a lever havingone end pivoted to said bar, a link pivotallyconnected to said spring and said lever, a bolt connected to eachof said pistons and having a pin and 7 prising a liquid under pressure for moving said piston outwardly in said chambers and spring means for automatically returning said pistons to theiroriginal position when the pressure is removed from the liquid,

said means comprising a spring secured to said bar, a lever having'one end pivoted to said bar, a link pivotally connected to said spring and said lever, a bolt connected to each of said pistons and having a pin and slot connection with the end of said lever.

.A hydraulic expansion bar having a chamber therein, a pair of opposed pistons in said chamber means comprising a liquid under pressure for moving said pistons outwardly in said chamber, and means for automatically returning said pistons to their original positions when the pressure is removed from the liquid. said means comprising a compression spring located in an opening in the bar and connected to the pistons by a system of levers.

6. A hydraulic expansion bar having chambers therein, a pair of opposed pistons in each of said chambers, means comprising a liquid under pressure for moving said pistons out- W-ardly in said chambers, and means for automatically returning said pistons to their original positions When the pressure is removed from the liquid, said means comprising a compression spring operating in an opening in said bar and connected to said pistons by a system of levers.

7. A hydraulic expansion bar having a plurality of chambers therein a pair of 0pposed pistons in each chamber, means comprising a liquid under pressure for moving said pistons outwardly in said chambers and spring means for automatically returning said pistons to their original position when the pressure is removed from the liquid, said means comprising a compression spring operatively connected to said bar and entirely enclosed therein, a lever having one end pivoted to said bar, a link pivotally connected to said spring and said lever, a bolt connected to each of said pistons and having a pin and slot connection with the end of said lever.

In testimony whereof I aifix my signature.

DAVY VANCE SIGKMAN. 

